Vienna is one of the grandest cities in the world. The seat of the Habsburg Empire for six centuries and a UN city since 1957, Vienna is a city where cultures have converged for untold generations - a tradition that is alive and well. Vienna's 23 districts are arranged radially around the legendary 1st District (Innere Stadt), surrounded by the Ring Boulevard and location of St. Stephen's Cathedral, the Hofburg, the Church of St. Charles Borromeo (Karlskirche), City Hall, Kärntnerstrasse, the Graben, the Vienna State Opera, the Museum of Fine Arts, the Albertina, and much more. The magnificent Belvedere and Schönnbrunn Palaces lie to the west and southwest of the 1st district, respectively. Heurigen (wine taverns), concentrated in Grinzing, are to the northwest. The Danube River skirts the city but is very much a part of it.